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The Impregnable Fortress (Azure Moon)

From Fire Emblem Wiki, your source on Fire Emblem information. By fans, for fans.
The Impregnable Fortress

Cg fe16 blue sea moon mural part 2.png
Mural used to introduce The Impregnable Fortress.


Garreg Mach Monastery


Death Knight

Previous chapter(s)

The Golden Deer's Plea

Next chapter(s)

Our Chosen Paths

You are finally here... Will death's scythe claim you... Or will I fall to that sword of yours... And Mercedes... Here you are as well...
— Death Knight

The Impregnable Fortress (Japanese: 鉄壁の要塞 Iron-walled fortress) is the twentieth chapter of Fire Emblem: Three Houses in the Azure Moon route.


Main article: The Impregnable Fortress (Azure Moon)/Script

As the Faerghus and Leicester forces consolidate, Dimitri declares that the group's next objective is to seize Fort Merceus, the last great hurdle between them and Enbarr, from the Death Knight. If the group discovered the Death Knight's true identity, Mercedes laments their upcoming conflict with her half-brother, but resolves to fight for what she believes in. Adrestia and Faerghus engage in battle, the Kingdom conquers Fort Merceus, and the Death Knight is slain; if his identity was discovered, he dies in a heartbroken Mercedes' arms. A soldier delivers a missive from Margrave Gautier revealing that order has been restored to Faerghus and that Kingdom reinforcements are on the way, and also reveals that a man claiming to have been involved in the Tragedy of Duscur was arrested.

Calendar - Blue Sea Moon

Blue Sea Moon
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
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2 3 4
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7 8 9
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10 11 12
Free Day Is ns01 free day.png
Saint Cethleann Day Is ns01 special day.png
Flayn's Birthday Is ns01 birthday yellow.png
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14 15 16 17 18 19
Free Day Is ns01 free day.png
Fish of Mystery Is ns01 fishing.png
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21 22 23 24 25 26
Free Day Is ns01 free day.png
Goddess's Rite of Rebirth Is ns01 special day.png
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27 28 29 30 31
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Character data

New Units


Returning Characters

Small portrait byleth f 02 fe16.pngSmall portrait dimitri 02 fe16.pngSmall portrait felix 02 fe16.pngSmall portrait ashe 02 fe16.pngSmall portrait sylvain 02 fe16.pngSmall portrait mercedes 02 fe16.pngSmall portrait annette 02 fe16.pngSmall portrait ingrid 02 fe16.pngSmall portrait ferdinand 02 fe16.pngSmall portrait linhardt 02 fe16.pngSmall portrait caspar 02 fe16.pngSmall portrait bernadetta 02 fe16.pngSmall portrait dorothea 02 fe16.pngSmall portrait petra 02 fe16.pngSmall portrait raphael 02 fe16.pngSmall portrait ignatz 02 fe16.pngSmall portrait lysithea 02 fe16.pngSmall portrait marianne 02 fe16.pngSmall portrait hilda 02 fe16.pngSmall portrait leonie 02 fe16.pngSmall portrait yuri 02 fe16.pngSmall portrait balthus 02 fe16.pngSmall portrait constance 03 fe16.pngSmall portrait hapi 02 fe16.pngSmall portrait anna fe16.pngSmall portrait catherine fe16.pngSmall portrait shamir fe16.pngSmall portrait cyril 02 fe16.pngSmall portrait flayn fe16.pngSmall portrait hanneman fe16.pngSmall portrait manuela fe16.pngSmall portrait alois fe16.pngSmall portrait seteth fe16.pngSmall portrait gilbert fe16.pngSmall portrait dedue 02 fe16.pngSmall portrait lorenz 02 fe16.png

Item data

This section has been marked as a stub. Please help improve the page by adding information.

Name Obtainment Method
Is ns01 seal.png Master Seal Tournament prize
Is ns01 axe.png Brave Axe Dropped by Caspar*/enemy War Master* in Taking Fort Merceus
Is ns01 potion.png Elixir Steal from Caspar*/enemy War Master*
Is ns01 potion.png Elixir Steal from Linhardt*/enemy Bishop*
Is ns01 potion.png Vulnerary Steal from Linhardt*/enemy Bishop*
Is ns01 bullion.png Extra Large Bullion Northeastern chest in Taking Fort Merceus
Is ns01 stat booster.png Black Pearl Southerneastern chest in Taking Fort Merceus


Main article: The Impregnable Fortress (Azure Moon)/Taking Fort Merceus

You received Failnaught at the end of the previous chapter. This weapon works best on Felix, Yuri, or Anna; of the other Crest-bearing archers, Bernadetta primarily uses bows for Encloser utility while Mercedes and Hanneman have magic-oriented stat spreads.

Etymology and other languages

Names, etymology and in other regions
Language Name Definition, etymology and notes

The Impregnable Fortress




Iron-walled fortress


La fortaleza inexpugnable

The impregnable fortress


La forteresse inexpugnable

The impregnable fortress


Die uneinnehmbare Festung

The impregnable Fortress


La fortezza inespugnabile

The impregnable fortress


철벽의 요새

Iron-walled fortress

Simplified Chinese


Impenetrable fortress; lit. "fortress with walls like iron"

Traditional Chinese


Impenetrable fortress; lit. "fortress with walls like iron"


This section has been marked as a stub. Please help improve the page by adding information.


The Golden Deer's Plea The Impregnable Fortress Our Chosen Paths
Fire Emblem: Three Houses
Playable characters Black Eagles BernadettaCasparDorotheaEdelgardFerdinandHubertLinhardtPetra
Blue Lions AnnetteAsheDedueDimitriFelixIngridMercedesSylvain
Golden Deer ClaudeHildaIgnatzLeonieLorenzLysitheaMarianneRaphael
Other AloisAnna*BylethCatherineCyrilFlaynGilbertHannemanJeritza*ManuelaSetethShamir
Ashen Wolves* BalthusConstanceHapiYuri
Non-playable characters Abysskeeper*Duke AegirLord ArundelCount BergliezFlecheGatekeeperDuke GerthGlennHolstIonius IXJeraltJudithLadislavaLambertMonicaNaderPatriciaRandolphRheaRodrigueRufusSeirosSitriSothisTomasTiana
Bosses AcheronAelfric*AloisLord ArundelBiasBlaiddydCasparCatherineCharonChilonClaudeCorneliaDaphnelDedueDeath KnightDimitriDominicBaron DominicEdelgardFelixFerdinandFlame EmperorFlaynFraldariusGautierGloucesterGonerilGwendalHubertIngridThe Immaculate OneThe ImmovableJudithKostasKronyaLadislavaLamineLinhardtLonatoLorenzMercedesMetodeyMiklanMysonNaderNemesisBaron Ochs*OdessePallardóPittacusRandolphRheaRieganRodrigueSetethShamirSolonSylvainThalesWandering BeastThe Wind Caller
Personal weapons and regalia Aegis ShieldAreadbharAsclepiusAthameAxe of UkonvasaraAymrBlutgangCaduceus StaffCirce StaffCrusherFailnaughtFetters of DromiFreikugelThe InexhaustibleLance of RuinLúinOchain ShieldRafail GemScythe of SarielSeiros ShieldSpear of AssalSword of BegaltaSword of MoraltaSword of SeirosSword of the CreatorTathlum BowThunderbrandThyrsusVajra-Mushti
Chapters Part I
White Clouds
Prologue: An Inevitable Encounter • 1: Three Houses • 2: Familiar Scenery • 3: Mutiny in the Mist • 4: The Goddess's Rite of Rebirth • 5: Tower of Black Winds • 6: Rumors of a Reaper • 7: Field of the Eagle and Lion • 8: The Flame in the Darkness • 9: The Cause of Sorrow • 10: Where the Goddess Dwells • 11: Throne of Knowledge • 12: To War Black Eagles, if Byleth sides against EdelgardBlue LionsGolden Deer / Outset of a Power Struggle Black Eagles, if Byleth sides with Edelgard
Part II Silver Snow
Silver Snow
13: Reunion at Dawn • 14: A King Without a Kingdom • 15: Valley of Torment • 16: The Rose-Colored River • 17: The Impregnable Fortress • 18: The Chaos of War • 19: Conclusion of the Crossing Roads • 20: The City Without Light • 21: Following a Dream
Azure Moon
Azure Moon
13: Reunion at Dawn • 14: The Delusional Prince • 15: Valley of Torment • 16: The Rose-Colored River • 17: Blood of the Eagle and Lion • 18: The King's Triumphant Return • 19: The Golden Deer's Plea • 20: The Impregnable Fortress • 21: Our Chosen Paths • 22: Oath of the Dagger
Verdant Wind
Verdant Wind
13: Reunion at Dawn • 14: The Alliance Leader's Ambitions • 15: Valley of Torment • 16: The Rose-Colored River • 17: Blood of the Eagle and Lion • 18: The Golden Scheme • 19: The Chaos of War • 20: Conclusion of the Crossing Roads • 21: The City Without Light • 22: Fódlan's New Dawn
Crimson Flower
Crimson Flower
13: Beyond Escape • 14: The Master Tactician • 15: Tempest of Swords and Shields • 16: Lady of Deceit • 17: Field of Revenge • 18: To the End of a Dream
Paralogues Paralogues Part I A Cursed Relic*An Ocean ViewBlack Market Scheme*Death TollDividing the World Black Eagles, if Byleth sides against EdelgardBlue LionsGolden DeerFalling Short of HeavenThe ForgottenLand of the Golden DeerOil and WaterRumored NuptialsThe Secret Merchant* Blue LionsGolden DeerSword and Shield of SeirosTales of the Red CanyonTrue ChivalryWar for the Weak Blue Lions
Part II Darkness Beneath the Earth Crimson FlowerDividing the World Silver SnowAzure MoonVerdant WindEternal Guardian Silver SnowAzure MoonVerdant WindThe Face Beneath Silver SnowAzure MoonVerdant WindForeign Land and SkyForgotten HeroInsurmountable Crimson FlowerLegend of the LakeRetribution Silver SnowAzure MoonVerdant WindThe Secret Merchant* Crimson FlowerThe Silver Maiden Azure MoonThe Sleeping Sand Legend Verdant WindWeathervanes of Fódlan Azure Moon
Cindered Shadows
(DLC side story)
Cindered Shadows
1: The Fourth House • 2: What Lies Beneath • 3: The Rite of Rising • 4: Danger in the Dark • 5: Betrayal • 6: Return to Me • 7: Wolf Pack
Locations Fódlan (AbyssAdrestiaFaerghusGarreg Mach MonasteryLeicester) • AlmyraBrigidDagdaSreng
Groups, objects and concepts 10 ElitesAshen WolvesBlack EaglesBlue LionsChildren of the GoddessChurch of Seiros (Knights of Seiros) • Crests (Crest Stone) • Divine PulseGolden DeerHeroes' RelicsInsurrection of the SevenMonstersThose who slither in the darkTragedy of DuscurWar of Heroes
Related topics Music LibraryName chart • Other games (Fire Emblem Warriors: Three Hopes) • Pre-release informationUnused contentDownloadable contentList of questsClass mastery